Paul Blart: Mall Cop successfully defended its No 1 position at the US box office at the weekend, but it was Danny Boyle's Oscar-tipped Slumdog Millionaire that made the real impact as a wide release combined with awards buzz to give the feelgood film the highest per-screen average in the top 10.

The tale of a teenager from the slums of Mumbai who finds himself one question from winning the Indian version of Who Wants to Be a Millionaire? took nearly a fifth of its tally so far – $10.5m (£7.5m) out of an 11-week total of $55m – to rocket up five rungs and claim fifth spot, with an average haul of $7,476 from each of the 1,411 locations.

Up until this weekend it had only been possible to see the film in limited US locations as studio Fox Searchlight opted to hold back from a full release in hopes of an awards season boost. That gamble more than paid off when the British film grabbed 10 Oscar nominations last week to add to its four Golden Globe wins. It was also honoured at the Screen Actors' Guild awards at the weekend with the best ensemble acting prize.

Paul Blart: Mall Cop, starring Kevin James as a mild-mannered security guard tasked with saving his local shopping emporium from a gang of crooks, was the overall frontrunner, with $21.5m in its second week. It beat off the challenge of new entry Underworld: Rise of the Lycans, the third instalment in the franchise, in which vampires and werewolves face off. Kate Beckinsale does not make a return appearance, and given the drop in its opening haul from $26.9m for Underworld: Evolution to $20.7m, it's more than possible that the series won't be back in multiplexes either.

The No 3 slot went to the Clint Eastwood drama Gran Torino, which continues to perform impressively with $15.9m in its seventh week – so well that pundits are predicting that it will pass the $100m mark next weekend.

The top five was rounded out by the family comedy, Hotel for Dogs, with $12.3m in its second week in fourth spot.

Elsewhere on the chart, new entry Inkheart, a fantasy adventure starring Brendan Fraser, Helen Mirren and Paul Bettany, opened poorly with just $7.7m. There was better news for another Oscar-tipped picture, David Fincher's epic romance The Curious Case of Benjamin Button, which crept back into the top 10 at No 9 with a haul of $6m in its fifth week.